Detection of integrated Sachs-Wolfe effect by cross-correlation of the cosmic microwave background and radio galaxies 中央研究院 Guo Chin Liu Collaborators: Ue-Li Pen (CITA) K-W Ng(IoP, AS) 2007/12/20@NTHU

Hubble Diagram with 42 High-Redshift Supernovae Something is missing for the “cosmological principle” based Friedmann universe. Standard candle? Evolution of SN Ia is small. D. Branch et al. 2001 Perlmutter et al. 1998 m+k+=1

Microwave Sky from WMAP CMB contains richest information of our universe. Expansion rate Age of universe Inflation model Content of universe Geometry of universe Thermal history (reionization) ……………

Statistics of CMB Sky Geometry of our universe ISW effect

Observation of CMB first peak alone does not guarantee the existence of dark energy. We are living in low density universe, i.e., m0.3. Allen et al. 2002 Carlberg et al. 1997 Hubble constant is not so small, for example, from SZ clusters measurement, H0=60-70 Reese et al. 2002 Udomprasert et al 2004. m+k+=1 Spergal et al. 2007

Astronomical Observation for Dark Energy Need to be sensitive on Geometry of universe (distance vs. redshift relation) 2. Structure formation Current used observations Supernova type Ia : probe the geometry of universe Caution: assuming uniform intrinsic luminosity CMB : good constraint on small curvature Caution : no time evolution data Large scale structure : evolution of geometry of universe and growth factor D(z) Caution: depend on CDM model for structure formation

Other possibilities Dark energy couples with cold dark matter : Changing matter power spectrum S. Lee, G. Liu & K. Ng PRD 2006 Coupling with CMB photons: Producing parity odd term in CMB polarization power spectra G. Liu, S. Lee & K. Ng PRL 2006

The physical quantity to be determined: Equation of state w(z)=p/ Cosmological constant: w=-1 Quintessence : wQ: w0, w0+(1-a)w1, oscillating…. a. Assume flat universe and const. w w=-1.05+0.15-0.2 Knop et al.2004 (SN) b. time evolution w=w0+ (1-a)w1 w0=-1.146+0.176-0.178 w1=0.6+0.622-0.652 --no dark energy perturbation w0=-1.118+0.152-0.147 w1=0.499+0.453-0.498 -- with dark energy perturbation G-B Zhao et al. 2006(SN+CMB+galaxy clustering) CDM explains observation data very well

Inhomogeneity Dark energy Cosmological constant

Cosmologists are often in error, but never in doubt 　Lev Landau

Future observation Weak lensing: Size of distortion image depends on distance traveled and growth factor BAO: Baryon Acoustic Oscillation is sensitive to dark energy through its effect on the angular-diameter distance vs. redshift relation and through its effect on the time evolution of the expansion rate. Clusters observation: growth rate and geometry of universe

Joint Efficient Dark-Energy Investigation (JEDI). SN Ia 0<z<2 Joint Efficient Dark-Energy Investigation (JEDI) * SN Ia 0<z<2 * BAO 10-100 M galaxies, 1000-10000 deg^2 * Weak lensing 1000-10000 deg^2 SuperNova Acceleration Probe (SNAP) *SN Ia 0<z<1.7 *Weal lensing

Second Hint from CMB ISW effect (late)I If the potential decays between the time a photon falls into a potential well and when it climbs out it gets a boost in temperature of due to the differential gravitational redshift and due to an accompanying contraction of the wavelength No ISW effect in matter dominate epoch. The dark energy dominating on late epoch creates the temperatures anisotropies on large scales. 1 2 E=|1-2| T/T=-2  d d/d

Try to look for correlation of CMB with matter ISW effect II Signature of dark energy Probe of evolution of structure Sensitive on large scale (horizon) Difficult to detect Try to look for correlation of CMB with matter

Cross correlation of CMB with matter in local universe Proposed by Crittenden & Turok (1996) Density fluctuation CMB gains energy Form structures Possible tracers NRAO VLA Sky Survey (NVSS) Hard X-ray background (HEAO-1) Sloan Digital Sky Survey (SDSS) Two Micron All Sky Survey Extended Source Catalogue (2MASS XSC)

Contribution to Signal from different Redshift Crittenden & Turok PRL 1996

First detection of the cross-correlation Correlating CMB sky to hard X-rays (HEAO-1) and radio galaxy (NVSS) wiNiwjTj/wiwj 3 sigma detection for hard X-rays and 2.5 sigma for radio galaxy Boughn & Crittenden, nature, 2004

Contamination Sunyaev-Zeldovich Effect: anisotropies generated through the inverse Compton scattering with free e- correlates with the galaxy itself. On small scales Emission from the radio galaxy Emission at f<few tens GHz contaminates the microwave sky. On small scales Primary CMB itself: △T(ISW) < 30% of △T(total)

Details of this work I We work at harmonic space SZ and radio emission is ignorable. Low correlation between each mode ClNT=<aNlmaT*lm> △T/T()=aTlmYlm() Using NVSS as matter distribution tracer. Healpix software is used for visualization and calculating alm

NVSS data 1. 1.4GHz , 82% sky coverage (>-40) 2. Sensitivity 2.5 mJy contains 1.8 million sources 3. Typical luminosity function models indicate 0z2 distribution

Detail II 41GHz 61GHz T T Q Q U U

Result I

CMB anisotropies & polarization on large scales CMB last scattering surface △TSW, z=1100 Generate P. for l>100 △Treion, z=10 Generate P for l < 30~50 △TISW, z<2 Dark energy dominates Observer

Correction by the information of polarization At large scales T=TSW + Tre + TISW E(no ISW) =aT(no ISW) + n <TE> = a <TT> <EE>=a2<TT> + n2 T(ISW) =T – E/a * WF WF=a2<TT>/<EE>

Result II

Discussion & Summary Working in harmonics space, signal with 2-sigma is detected in l~ 10-20. Though it is smaller than detection in real space, statistically it gives same information. Primary CMB is the dominated noise in this cross-correlation. Using polarization information, we can filter out part of it. It suppress the noise about 17%, 3% and 8.7% in band power l=3, 7 and 15. Give a better constrain on dark energy model.